Numbers n such that 2*10^n + 8*R_n + 1 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

A102963

Numbers n such that 2*10^n + 8*R_n + 1 is prime, where R_n = 11...1 is the repunit (A002275) of length n.

Terms

    a(0) =0a(1) =1a(2) =7a(3) =8a(4) =11a(5) =14a(6) =19a(7) =32a(8) =41a(9) =53a(10) =61a(11) =133a(12) =157a(13) =239a(14) =1237a(15) =30254a(16) =34423a(17) =139289

External references